Two examples are provided of chiral molecules where the racemic mixtures display different adsorption behavior than the individual enantiopure components.  In the first, in-situ infrared absorption spectroscopy data are provided to show the differences in 1-(1-naphthyl)ethylamine (NEA) uptake onto platinum polycrystalline surfaces from solution.  When using racemic mixtures, new features are observed, presumably associated with the 1:1 H-bonded pairing of (S)-NEA with (R)-NEA.  The second example refers to the uptake of propylene oxide (PO) on Pt(111) under vacuum.  In this case, the lower saturation coverages seen with the racemic mixtures, as measured by TPD and molecular beam experiments, have been explained by kinetic effects.  No long-range order or evidence of individual molecular pairing was seen by STM.

Differences in adsorption between enantiopure and racemic mixtures of chiral compounds on platinum surfaces

245th National Meeting (2013)

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